package jdbc;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class JDBCDemo7 {
    public static void main(String[] args) {
        try(Connection conn = DBUtil.getConnection()){
            Statement stmt = conn.createStatement();
            String sql = "SELECT COUNT(*) count "+
                         "FROM student s, class c " +
                         "WHERE s.class_id = c.id " +
                         "AND c.name = '1年级1班'";
            ResultSet rs = stmt.executeQuery(sql);
            if(rs.next()){
                int count = rs.getInt("count");
                System.out.println("1年级1班共有"+count+"人");
            }
        }catch (SQLException e){
            e.printStackTrace();
        }
    }
}
